Add support for multiple Linear teams to LinearCreateIssueTool

[codegen-sh]

This PR adds support for multiple Linear teams to the LinearCreateIssueTool and other Linear tools.

Changes

1. Updated all Linear tools to be initialized with a Codebase object instead of a LinearClient
2. Added a _get_client() method to each Linear tool that creates a LinearClient on demand
3. Specifically for LinearCreateIssueTool, ensured it initializes the client without a default team_id to allow explicit team selection
4. Added a test file that specifically tests creating issues with explicit team_id values

Testing

Added a new test file tests/integration/extension/test_linear_team_id.py that verifies:

• Creating issues with explicit team_id values
• Testing with multiple teams when available

This fixes the issue where LinearCreateIssueTool was defaulting to the first team in the list and not respecting the specified team_id.

Fixes CG-12122

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